Micro-electrical-mechanical device and method of making same

Abstract

A micro-electro-mechanical device including a first substrate; a first contact disposed on a first surface of the substrate; a piezoelectric actuator disposed over the first surface of the substrate; a second contact coupled to the actuator and disposed in proximity to the first contact; a gap control mechanism disposed between the substrate and the actuator for limiting movement of the first contact relative to the second contact. In the exemplary embodiment, the gap control mechanism is a gap control stop constructed of dielectric material. In practice, plural stops are used. In the exemplary embodiment, plural thermosonic bonds are used to connect the actuator to the first substrate. A second substrate is disposed over the piezo-electric actuator. The second substrate has wells over the bonds to facilitate application of a bonding tool to the bonds. The gap control mechanism provides consistent height control between a flipped chip and its base substrate without exposing the assembly to high temperatures.

1. A micro electromechanical device comprising:
 a first substrate; 
 a first contact disposed on a first surface of said substrate; 
 a piezoelectric actuator disposed over said first surface of said substrate; 
 a second contact coupled to said actuator and disposed in proximity to said first contact; and 
 a gap control means disposed between said substrate and said actuator for limiting movement of said first contact relative to said second contact. 
 
   
   
     2. The invention of  claim 1  wherein said gap control means includes a first gap control stop. 
   
   
     3. The invention of  claim 2  wherein said control stop is a dielectric material. 
   
   
     4. The invention of  claim 2  wherein said gap control means includes a second gap control stop. 
   
   
     5. The invention of  claim 1  further including plural bonds between said actuator and said first substrate. 
   
   
     6. The invention of  claim 5  wherein said bonds are thermosonic gold—gold bonds. 
   
   
     7. The invention of  claim 6  further including a second substrate disposed over said piezo-electric actuator. 
   
   
     8. The invention of  claim 7  wherein said second substrate has wells over said bonds to facilitate application of a bonding tool to said bonds. 
   
   
     9. The invention of  claim 1  further including a layer of metallization under a second surface of said second substrate. 
   
   
     10. A micro electro mechanical variable capacitor comprising:
 a first substrate; 
 a first contact disposed on a first surface of said substrate; 
 a piezoelectric actuator disposed over said first surface of said substrate; 
 a second contact coupled to said actuator and disposed in proximity to said first contact; and 
 a dielectric material disposed between said substrate and said actuator for limiting movement of said first contact relative to said second contact.